Amp draw shows 0.0 from (-) post to (-) cable...?

[Schrade]

I DO have something taking down the battery (amongst the other problems with the stick-to-auto swap)...

Battery tested VG at Advance / Zone (bought an Optima anyway; not installed), but isn't the proper way to test for draw, through the (-) terminal???

Haven't tested through the (+) side yet...

:confused:

[scottfab]

I DO have something taking down the battery (amongst the other problems with the stick-to-auto swap)...

Battery tested VG at Advance / Zone (bought an Optima anyway; not installed), but isn't the proper way to test for draw, through the (-) terminal???

Haven't tested through the (+) side yet...

:confused:

Not sure I understand the question. Current tests are from - to + terminal with a known load over a specific period of time like 10 seconds.
The battery voltage should not go below the specified level (battery type dependent)

[efnfast]

Amp draw can only be done with a wrap around amp meter, and it must be for dc. Check on the positive cable. Don't know what the normal draw would be. I'll go check, be right back.

[efnfast]

Yea right, not a prayer of wrapping an amp meter around the positive cable.

[vilant]

I think he's talking about a split ring amp probe, that's what I have. I does have ac/dc settings, but I've never amped out a dc circuit before, just ac circuits.

[scottfab]

Amp draw can only be done with a wrap around amp meter, and it must be for dc. Check on the positive cable. Don't know what the normal draw would be. I'll go check, be right back.

Current draw can in fact be done without a wrap around amp meter. Even cheap meters from Harbor Freight ( $3.00) can measure up to 10 amps. You can do this at the - or + post (doesn't matter) by disconnecting one or the other and putting the meter in series (making sure to get the polarity right).

For anything higher than 10 amps you can still do it without a wrap around amp meter. You need a known low value resistor in series (0.1 ohm) then measure the voltage across the resistor. 1V will be 10amp draw. There are resistor made exactly for this purpose. They are precision high power resistors. The last one I used was in a 5 battery array to measure charging current. It was a permanently installed setup.

[WVZR-1]

Aren't we wanting to check for a "Parasitic Draw" here? That can be done easily with the DVOM in a series using the negative cable and the negative battery post with the DVOM set to AMPS. It can actually be done using either neg or positive but there's less of an opportunity to "fry" electronics if it's done using the negative cable and negative post. Generally speaking I'd guess we're looking for something 50Ma or less. Greater than that there's certainly something amiss.

All relays, fuses require a check. I'd guess check the "draw" and see what you've got. It needs to be done with a battery that is "fully charged"! Start with the DVOM I guess at it's lowest AMP setting not Ma for starters. Doors shut, lights off, hood lights maybe disconnected, check courtesy light, glove box console etc. Keys in your pocket!!

If you had no significant draw you could change to the Ma setting and recheck.

You mention 0 presently so I'm guessing you're using something high on your DVOM setting. Try 10 or 20 if you can, recheck and if still insignificant change to Ma and check. Are the leads in your DVOM in the correct ports of the meter. AMPS DC, Ma DC sometimes require the leads be swapped on the meter.

BTW - Consider the return of the Optima !! Red or Yellow seem to have issues. There's much to say around regarding them.

[Paul Workman]

Aren't we wanting to check for a "Parasitic Draw" here? That can be done easily with the DVOM in a series using the negative cable and the negative battery post with the DVOM set to AMPS. It can actually be done using either neg or positive but there's less of an opportunity to "fry" electronics if it's done using the negative cable and negative post. Generally speaking I'd guess we're looking for something 50Ma or less. Greater than that there's certainly something amiss.

All relays, fuses require a check. I'd guess check the "draw" and see what you've got. It needs to be done with a battery that is "fully charged"! Start with the DVOM I guess at it's lowest AMP setting not Ma for starters. Doors shut, lights off, hood lights maybe disconnected, check courtesy light, glove box console etc. Keys in your pocket!!

If you had no significant draw you could change to the Ma setting and recheck.

You mention 0 presently so I'm guessing you're using something high on your DVOM setting. Try 10 or 20 if you can, recheck and if still insignificant change to Ma and check. Are the leads in your DVOM in the correct ports of the meter. AMPS DC, Ma DC sometimes require the leads be swapped on the meter.

Just remember to remove the test leads from the circuit being measured BEFORE changing scales on the meter, especially when measuring current! After selecting the ampere range, then reconnect the test leads. Otherwise, at the very least, there may be some arching at the meter's internal switch contacts that could be damaged.

Just a thought.

P.

[Schrade]

Current draw can in fact be done without a wrap around amp meter. Even cheap meters from Harbor Freight ( $3.00) can measure up to 10 amps. You can do this at the - or + post (doesn't matter) by disconnecting one or the other and putting the meter in series (making sure to get the polarity right).

That's what I should have done...


Aren't we wanting to check for a "Parasitic Draw" here? That can be done easily with the DVOM in a series using the negative cable and the negative battery post with the DVOM set to AMPS. It can actually be done using either neg or positive but there's less of an opportunity to "fry" electronics if it's done using the negative cable and negative post. Generally speaking I'd guess we're looking for something 50Ma or less. Greater than that there's certainly something amiss.

All relays, fuses require a check. I'd guess check the "draw" and see what you've got. It needs to be done with a battery that is "fully charged"! Start with the DVOM I guess at it's lowest AMP setting not Ma for starters. Doors shut, lights off, hood lights maybe disconnected, check courtesy light, glove box console etc. Keys in your pocket!!

If you had no significant draw you could change to the Ma setting and recheck.

You mention 0 presently so I'm guessing you're using something high on your DVOM setting. Try 10 or 20 if you can, recheck and if still insignificant change to Ma and check. Are the leads in your DVOM in the correct ports of the meter. AMPS DC, Ma DC sometimes require the leads be swapped on the meter.

BTW - Consider the return of the Optima !! Red or Yellow seem to have issues. There's much to say around regarding them. YUP!


Just remember to remove the test leads from the circuit being measured BEFORE changing scales on the meter, especially when measuring current! After selecting the ampere range, then reconnect the test leads. Otherwise, at the very least, there may be some arching at the meter's internal switch contacts that could be damaged.

Just a thought.

P.YEP; 'manual' said (I think published by Chilton or Haynes), said nothing about removing the probes before changing range. Manual ALSO said use ONLY the fused circuit to measure DC current. Only the 10 AMP UNfused circuit showed me the draw, which I found in MANUFACTURER'S .pdf on the web :mad:

AND, that circuit is good for < 10 sec measurement, ONCE EVERY 15 MINUTES!!! How many fuses can you pull in < 10 seconds :confused:

That's what I got for buying a 4M widget DT830 (Mickey Mouse Multi-Meter) :o

So I traded it in for a 4M Gen II CP 7677 :dancing

https://lh4.googleusercontent.com/-fouJZOaABfQ/UfJlSp4bURI/AAAAAAAABm0/SASfQXic6kQ/s1280/IMG_5556.JPG

I'll find that amp draw, or ELSE (or else, watch for the magic smoke that makes electronics, until the smoke gets out, like so:

https://encrypted-tbn1.gstatic.com/images?q=tbn:ANd9GcQnpep1DvzuRdlU3v8QjCPUBRZ0XWGRi BA3lzeQMlb39pl326u3

[WVZR-1]

Check using the 10A fused first and see what value is displayed. If you're 1.xxxx or better then there's an obvious situation. When you're ready to check circuits you should be able to clamp one lead to the battery (-) post and the other to the cable, keeping the meter in viewing sight start removing fuses and checking the meter. Screw a 3/8 bolt into the battery, clamp to that.

[Schrade]

Check using the 10A fused first and see what value is displayed. If you're 1.xxxx or better then there's an obvious situation. When you're ready to check circuits you should be able to clamp one lead to the battery (-) post and the other to the cable, keeping the meter in viewing sight start removing fuses and checking the meter. Screw a 3/8 bolt into the battery, clamp to that.

YESSIR there Dave... :thumbsup: Thanks...

I did get a steady 2.6 amp display, on the cheapo 10A UNfused port, but after a few moments, it went to zero. 2.6A SHOULDN'T have pegged it... :mad:

Haven't plugged in the new one yet (I hope it will hold the draw in display, as I pull plugs in the fuse box.

[Paul Workman]

YESSIR there Dave... :thumbsup: Thanks...

I did get a steady 2.6 amp display, on the cheapo 10A UNfused port, but after a few moments, it went to zero. 2.6A SHOULDN'T have pegged it... :mad:

Haven't plugged in the new one yet (I hope it will hold the draw in display, as I pull plugs in the fuse box.

When connecting the meter in series with (either) battery cable and the battery post, an initial surge is to be expected, as the capacitors in the various electronics will discharge in the interim after the cable is removed from the battery.

Then when the meter is connected, there is an initial current surge until the capacitors are charged again. After a few seconds, the current will settle to a steady state. It is that steady state flow that is of interest, far as battery drain goes.

Various GM vehicle manuals/sources pertaining to computerized cars indicate 50mA (or 0.05A) is acceptible. I don't remember zackly what it was for my 90 Z, but I wanna say it was no more than half that (25mA) if I recall. (Of course the everything has to be turned off; e.g., console and courtesy lights, etc.).

Far as which cable - positive or negative - to disconnect (when taking a direct reading) goes, as Scottfab indicated, whichever is the more convenient is fine. (That would be the negative cable in the case of the Zs.)

Then as far as which meter lead goes where, the RED lead goes to the positive battery post and the BLACK goes to the loose end of the cable. OR...visa vera if the negative cable is removed i.e., BLACK LEAD TO THE BATTERY, RED LEAD TO THE LOOSE NEGATIVE CABLE...in other words.

WARNING! When finished with the current measurement, return the meter leads to the normal (voltatge) measurement configuration. More than once I've taken a current reading, set the meter down without switching the leads back, and then forgetting and picking up the meter to take a VOLTAGE reading and POP! goes the dang fuse!:mad: And, if you're lucky, if that's all that happens.:cry:

P.

[Schrade]

Aren't we wanting to check for a "Parasitic Draw" here? That can be done easily with the DVOM in a series using the negative cable and the negative battery post with the DVOM set to AMPS.It can actually be done using either neg or positive but there's less of an opportunity to "fry" electronics if it's done using the negative cable and negative post. Generally speaking I'd guess we're looking for something 50Ma or less. Greater than that there's certainly something amiss.

All relays, fuses require a check. I'd guess check the "draw" and see what you've got. It needs to be done with a battery that is "fully charged"! Start with the DVOM I guess at it's lowest AMP setting not Ma for starters. Doors shut, lights off, hood lights maybe disconnected, check courtesy light, glove box console etc. Keys in your pocket!!

If you had no significant draw you could change to the Ma setting and recheck.

You mention 0 presently so I'm guessing you're using something high on your DVOM setting. Try 10 or 20 if you can, recheck and if still insignificant change to Ma and check. Are the leads in your DVOM in the correct ports of the meter. AMPS DC, Ma DC sometimes require the leads be swapped on the meter.

BTW - Consider the return of the Optima !! Red or Yellow seem to have issues. There's much to say around regarding them.

This seems to make more sense - to measure the draw on the negative side...

Because ... (this is a guess - I don't know for sure)

If there's a 'Short To Ground' (-), on the positive (+) side of the battery, that would [have a greater effect ???] on the DVM's circuit board, ... than if the negative (-) side of the battery's ground connection had a short to a wire on a positive (+) circuit.

Dave???

Why do you say 'less chance of cooking' DVM innerds, by testing for parasitic Amp draw, on the negative side?

[Paul Workman]

Ah... U is makin dis harder than it needs to be...

The battery is a pump. What goes out (current) must come back...ALL of it. So, it doesn't matter which cable you pull off and insert the meter at, either will work equally well with no special liabilities (once either terminal is removed).

With all the doors closed, lights off, ignition switch OFF begin by:

switching your meter to the DC Ampere setting.
move the red lead to the port on the left bottom of you meter (pictured) that has the "A" above it.
If you've chosen the negative (-) post, the red lead on the meter will be connected to the removed negative terminal, and the black lead goes to the negative (-) post on the battery. (If you choose the POS cable, do everything the same, except the red lead connected to the "A" terminal of your meter will go to the POS post of the battery, and the black lead will go to the POS battery cable connector.)

Note: Ordinarily there are some circuits that will become discharged within a few seconds of removing a battery terminal; removing the POS especially. So, when you first connect the meter in series between the battery cable connector and the battery post, there will usually be a current surge. This is normal. As soon as the circuits that are normally kept alive with the ignition switch OFF are charged up, the surge will taper off and usually within 5 seconds (certainly by 10 seconds) the current will settle down and the meter will display the leakage current you're interested in.

In rare cases, initial surge current can be so high that it might exceed the limit of the meter. However, if you make your chosen meter connections to the battery and to the battery connector FIRST, AND THEN separate the battery cable from the battery post, while maintaining the meter connections between the battery cable and the battery post, you will avoid the normal high surge, and the reading will settle immediately to the leakage value.

GM says (generally) up to 50mA (0.05A) is "normal". I find that to be a bit high; about 35mA (.035A) is more likely. If you experience anything close to 1.0A or more, it is time to pull fuses one at a time until you locate the circuit with the excessive draw, and go from there.

[scottfab]

Battery current draw values are on page 6D1-4 of the FSM.
Depending on what the battery V is your draw should be
about 15ma with the key out and leaving the car long enough
to go to sleep. (~30 seconds)
If you have after market electronics (alarm etc) the current
could be higher.

Measuring at the NEG side of the battery to ground has the
advantage only of not popping the fuse in the meter if you slip
and touch ground with either lead.

[Schrade]

Thanks there guys...

I pulled up this old thread for info for pablopicasso46 (http://www.zr1.net/forum/showthread.php?t=21114) to consider, with his no start condition...

I understand relatively well flow of juice in a circuit...

Electricity flow is like water in a hose (except for the taste - more on that in a moment). If it ain't gettin' to the end of the hose, it's leakin' somewhere upstream.

Hole in hose, water all runs out = short to ground. Like pablopicasso's battery...

Connected hose doesn't mean water is flowing either. Spigot must be turned on, and still it might not flow, unless the hose water gun is releasing water to [ground].

Hole in hose means not enough water to spin the water wheel.

Squeeze the hose water gun just a LITTLE (like a corroded ground connection), no full flow / bad 'ground', and the light bulb is dim, or LCD dash flickers.

Fuse blows (hose pops a blister and ruptures) when there's too high water pressure for the hose.

And, they taste different. You can even use your organic analogue multimeter (snappic below) to find voltage - like on old-style 9V transistor radio batteries. Louder scream is proportionate to higher current :mrgreen:





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